Light-regulator for electric lamps.



T. E. MURRAY.

LIGHT REGULATOR IOR ELECTRIC LAMPS. APPLICATION FILED PEB.11. 1907.

908, 1 1 7. Patented Dec. 29, 1908.

2 SHEETS-SHEET ,1.

W|TNE$$E$= 1. i I INVENTOR 614% Y #9 ATTORNEY T.- E. MURRAY.

LIGHT REGULATOR FOR ELECTRIC LAMPS.

APPLICATION FILED FEB.11. 1907.

908, 1 1 7, Patented Dec. 29, 1908.

2 SHEETS-SHEET 2.

INVENTOR ATTORNEY plates 14 and the under sides of perforated plates.17, 18, are

"THOMAS" MURRAY, or nnwfroaxpnr.

LI GET-RE GULA'I. OR FOR ELECTRIC JLAMPS- Specification of LettersPatent.

Patented Meet,- 1908.

Application filed February 11,.1907.. Serial No. 356,836.

To. allwhom it may. concern:

Be it known that I; THOMAS E. MURRAY, a. citizen ofntheUnited-States,residing at New York, in the county of New York and State'of N ew-York,.have invented a certain new.-and useful Improvement in Light-'Regulatorsfor Electric Lamps, of which the following is aspecification.-

The invention. is an, apparatus for-increasing ordiminishing'theintensity of the light emitted by=an eleotriclamp by producing, in..thelamp circuit currentvariationsof predetermined. frequency and varyingthe relativecperiodicities of saidvariations.

The invention consists in the construction of the device and the meansfor supplying liquid (llBl6OtIlC. t0 the contacts,. as more particularlyset forth. in the claim.

.In. the. accom anying. drawings, Figure 1.. is. a horizonta sectiom of..the apparatus .011 the .line a: a:.-of Fig. 3. .Eig- 2. is a section onthe=line y y of Fig. 1. Hi 3.is a vertical-section on .the line 2 z. ofFig. 4.is a plan vieW'of the le-verand associated erforatedplate.

Simi ar-numbers. of .referenceiindicate like parts. I

ylindrical: box filled with oil or other liquid dielectric (not shown).

2 is a central shafthavingits. lower por- 3 insulated from tion disposedin \a' etc the flange 4, above box 1, and provided wit which'said shaftpasses through the insulated bearing 5 and is connected to the shaft ofa motor 6, by the ordinary flanged coupling 7. The motor may besupported by a bracket 8 on the coverplate 9 of box The central shaft 2Within the box is squared at-11, to receive the hubs 12 of the metalcontact plates 13, each having a plurality of arms. Between the arms ofeach contact plate 13 are perforated plates 14 ofrubber or other hardinsulating material which are sup orted by the metal strips 15 securedto t e under sides of said plates 13, in any suitable way. The 14 arecut away around the shaft 2 to form a central aperture at 16, and twoopenin s ormed in each plate on one si e of each arm of each contactplate 13. On

the under sides of the said plates14 and extending below in front ofsaid openings and also extending radially across .the central a erture16 are buckets 19, 20, 21, having t eir concavities turnedin the shaftcarries a surface of..the..eontactdplates 13. .and

-sameiplane, t

Fig. 1,.and

-13 to shaft 2 grammatical same. (direction, those of the buckets .19,

20, being below. openings 17,. .18.

: 22. is. a .-shaftdisposed in. aprojecting portion 23nOf box 1,received at. its lower ..end-.in a stepb24- (dotted lines Fig. 3) andpassing throu h aninsulated bearihg 25 .in thecover p ate. 9. At itsupper and said ever 26, which extends-over aperforated late27hsupportedin cover 9 -and is provi ed. with a vertically movableheaded. pin-28, wl1ich..may be insertedin any=opening .in-plate 27.Within the. box 1 the shaft v22rcarries aseries of collars v29, eachfaston the shaft and each provided with an arm- 30,.hav ing.atzi-ts endacontact spring 31 bent-to resent a flat-surface'on its. under. side.:liiasmuch as ..the 11 per 7 o the erforate plates 1 4 I are .inlthe fiecontactsprings alwaysbear eithenon the armaofthe contactplates-13 or'lonthe .intermediataplates .14.

The .icircuit z in the v.a paratus. proceeds from the-bearing. 25 to.slihft 22 toithe several. contact springs 31, to. contact plates andbearing. 5. The bearings 5. and 25=maybe connected with anydesirednumber of low lights .as indicated ..dia-

y at 32.

intermediate he operation of .the deviceidepends upon .ithefprinciplefir st,lthat thehumaneye 1811111- able to recognize interruptions in aray from a luminous focus, if the frequency of said interruptionsexceeds a certain rate er second; second, that the luminous intensity ofthe apparently unbroken ray can be varied by varying the duration of theintervals. T e resulting ph sical effect on the eye is that of anunbrolien ray which is decreased or increased in luminous intensity atwill. Assume now that the shaft 2 is rotated by electric motor 6, sothat the arms of the contact plates 13 move in the direction of thearrow in Fig. 1. Obviously circuit will be completed to the lampswhenever the arms of t e metal contact plates 13 come under the springs31, and for a period represented by thedistance in are a, b, in Fi' 1.Circuit will be broken during the perio represented by the distance inarc b, 0, when the insulating plate 14 runs under the spring. The specof rotation of shaft 2 is, however, to be such that the number of makesand breaks in the circuit to the lamps, or in other words, the number ofinterruptions of current in the lamp circuit-is to be greater per secondthan is moved outwardly and decreased as it is the luminous intensit theeye can appreciateI Now suppose the arm 30 to be swung outwardly byturning its shaft 22, so that the center line of said arm comes to theposition b" Fig. 1. Then the eriod of time during which circuit is madeto the lamps is somewhat reduced, and is represented by the distance inare a, I), while the period during which the circuit is broken,represented by the distance in are b c is greatly increased. On theother hand, if the arm be swung inwardly so that the center line of saidarm comes to the position b then the period of time during which circuitis made to the lamps is somewhat increased and is represented by thedistance in are a 5, while the period during which the circuit is brokenrepresented by the distance in are l) c is greatly decreased. In otherwords, as the arm is swung on its shaft the relation of the periods ofmake and break is altered, the break periods being increased as the armmoved inwardly.

In practice the arm 30 is moved to its outermost osition and the speedof the shaft 2 is regu low thus indicating that although the rea in thecircuit are at a maximum with respect to the makes, they are occurringwith a frequency too great for the eye to recognize them. The degree ofvluminosity of the lamps will then bear a relation to the relativeperiodicities of the makes and breaks and be at a minimum. As the arm 30is moved inward these relative periodicities change, and as those of thebreaks constantly diminish 'of the lamps con stantly increases, so t atinorder to vary said intensity it is simply necessary to turn the arm 30in one direction or the other by ated until the lamps show steadyv mdially disposed contact means of lever 26, and when the desired intensity is obtained the lever may be secured by inserting pin 28 in theproper aperture of plate 27.

The object of filling the box 1 with oil is to prevent sparking orarcing as the contact arms run from under the springs 31, and this isstill further avoided by means of the buckets which constantly take upthe oil and project it in streams through the adjacent openings.

Une ractical application of the device to which y actual experiment Ihave found it applicable is the regulation of the intensity of numerousglow lamps simultaneously. Thus in theaters and public halls, the,lights can be raised or lowered as gradually as may be desired and toany chosen degree, and be held indefinitely at any selected intensity.

it will also be noted that the present device entirely obviates thenecessity of the introduction in the lamp circuit of resistance coils orother energy consuming contrivances in order to vary the luminosity ofthe lamps.

I claim I The combination of a box for containing a liquid dielectric, arotary shaft therein, a ralate on said shaft, a contact v supported inependently of said shaft, bearing, on the surface of said plate andmovable in a direction radial to said shaft and buckets on said. platehaving inclined surfaces for projecting said dielectric upon the bearingsurface of saidcontact. In testimony whereof l have afiixed my signaturein presence of two witnesses.

THOMAS E. MURRAY.

- Witnesses:

PETER P. SMITH, ARTHUR H. Sronn.

